Subgrate drain basin filter

ABSTRACT

The invention is a filter mounted below a perforated basin cover ( 12 ) of a storm water inlet basin ( 10 ) suspended from two ridged support bars ( 22 ) which rest upon a cover support ( 26 ) which are connected to a bag assembly ( 28 ) by inserting the support bars ( 22 ) into two bar sleeves ( 24 ) on a periphery of a filter basket ( 16 ) with a storm water bypass comprising a loop ( 14 ) and a bridge ( 18 ) which channels water above and over the loop into the inside of a filter basket ( 16 ).

REFERENCES CITED

[0001] U.S. Patent Documents U.S. Pat. Documents 1,746,121 February 1930 Adolph Levi 2,102,310 December 1937 George F. Egan 2,615,526 October 1952 F. Lane 4,419,232 December 1983 Oscar S. Arntyr et al. 5,575,925 November 1996 Logue, Jr. 6,045,691 April 2000 Holly S. McDermott

[0002] U.S. patent application Ser. No. #09/769,212 Grp Art unit 1724 John F. Harris and Ardle E. Page

BACKGROUND FIELD OF INVENTION

[0003] This invention relates to a filter for use inside storm water inlet basins, beneath perforated covers such as perforated manhole receptacles and catch basins with grates.

BACKGROUND-DESCRIPTION OF PRIOR ART

[0004] Storm water collection systems are located throughout our city streets and parking lots providing flood control and drainage. The storm water needs to be as free as possible from pollutants before it enters our natural water systems such as streams. To ensure that our water sources are protected our handling of storm water is becoming more regulated. In order to meet these concerns, many inventions have been patented that provide an anti pollution support filter insert systems for catch basins and manholes. Most of these inventions are unnecessarily expensive. The present invention pertains specifically to storm water inlet basins with perforated top covers.

[0005] Caldwell (U.S. Pat. No. 1,310,055) develops a storm water device to strain out large debris such as sticks and leaves and allows them to be broken up before passing down stream or be removed manually. This apparatus is ineffective in separating sand or small particulate such as cigarette filters from the storm water before flowing downstream from the opening.

[0006] A Levy (U.S. Pat. No. 1,746,121) and George F. Egan (U.S. Pat. No. 2,102,310) show a receptacle for mounting below a storm water inlet. The large basket is constructed of metal. It is heavy and very complex. This would be very expensive to manufacture. They both require large equipment to install, and maintain.

[0007] F. Lane (U.S. Pat. No. 2,615,526) shows a basket mounted entirely below a catch basin grate. It comprises a ridged metal frame for the basket, which is suspended from rods secured directly to the bottom of the grate. This would be very time consuming and awkward to install, A grate is already heavy and hard to handle. The frame when attached to the grate would be difficult to install without damaging the metal frame. Furthermore its complexity makes it expensive to manufacture.

[0008] Oscar S. Arntyr et al. (U.S. Pat. No. 4,419,232) shows a double basket mounted entirely beneath a storm drain opening and grate. The device is unnecessarily complex. The initial top screen basket is unnecessary. It removes pollutants that would have been removed by the below second filter anyway. The second stage basket cannot be serviced or emptied by hand unless the whole frame is removed. The ridged frame cannot be easily adapted to the various sizes of grates and their angular distortions at typical installation sites. The frame with its descending circumference is unnecessarily complex and expensive to manufacture. There is no provision for a by pass to accommodate high flows or filter failure.

[0009] Logue, Jr. (U.S. Pat. No. 5,575,925) and John F. Harris et al. (U.S. patent application Ser. No. #09/769,212 Grp Art unit 1724) show a basket essentially below the grate of a drain opening. A substantial amount of the apparatus extends above the grate. This can be a traffic hazard. They are exposed to wear and vandalism. They also do not have a bypass provision. During high storm water flows and filter failure they would back water up into the street.

[0010] Holly S McDermott (U.S. Pat. No. 6,045,691) shows a receptacle entirely below a storm water inlet with a perforated cover. The receptacle however is limited in pollutant storage capacity. There are four separate baskets, one on each comer, which makes it, time consuming to service. They need to be manually emptied since they are too small for being serviced by a typical large street vacuuming machine. The fixed frame mounting does not easily adjust to the various distorted angles encountered in many rectangular storm water inlet openings at the installation sites. The drain basins are often out of square or of slightly different measurements than anticipated. The frame is unnecessarily expensive to manufacture. The pollutant sock is small in size and would quickly saturate.

[0011] The disadvantages of the prior art are as follows:

[0012] a) They have filter receptacles that are too large and heavy to easily service by hand, or too small to service by a street vacuuming machine.

[0013] b) They have strainers with hydraulic openings that are too large to filter out small particulate such as sand or gravel.

[0014] c) They require complex and awkward installation procedures.

[0015] d) When installed, they leave essential parts of the filter apparatus above the cover of the inlet basin where they are exposed to where, vandalism and can pose a traffic hazard.

[0016] e) They do not have a functioning bypass for high water flows or filter failure.

[0017] f) They do not have adequate storage for pollution particulate.

[0018] g) They are unnecessarily complex and expensive to manufacture, ship and install.

[0019] h) They do not easily adapt to specific requirements encountered in the variety of inlet basin with their individual distortions.

OBJECTS AND ADVANTAGES

[0020] Accordingly, my invention provides a filter with a support structure and filter basket which is inexpensive to manufacture, and is easy to install, remove, or service. Several objects and advantages of the present invention are to provide a filter:

[0021] a) with a support structure which is easy to install by hand without the aid of power tools;

[0022] b) with a support structure which is flexible at the corners and can be easily trimmed by hand tools to fit unexpected resizing at the installation site;

[0023] c) with a support structure that is entirely beneath the inlet cover and does not interfere with the normal flow of street traffic including machinery such as snow plows;

[0024] d) that is essentially not subject to vandalism;

[0025] e) that essentially removes solid pollutants from storm water before it passes out of the inlet basin and retains these pollutants beneath the perforated inlet cover and not is the street;

[0026] f) comprising a support structure and bag assembly that can serve either as a temporary or a permanent Storm Water Pollution Prevention Plan;

[0027] g) with a filter comprising a support structure that can position an absorbent medium for absorbing chemical pollutants such as hydro carbons and oils;

[0028] h) which comprises a simple by-pass during high flows or a filter failure such as when the openings of the filter basket are blocked and the water cannot flow through the filter;

[0029] i) that has a support structure that comprises off the shelf items such as angle iron or 2″ galvanized steel strap;

[0030] j) that has a support a structure with a simple design which is inexpensive to manufacture;

[0031] k) that can be easily serviced by either emptying by hand or vacuuming by a street vacuuming machine;

[0032] l) with a filter basket that is easily attached or detached from its support structure by means of enclosure of a portion of the structure by a simple sleeve formed in the basket peripheral edges.

[0033] Further objects and advantages of my invention well also become apparent from a consideration of the drawings and ensuing descriptions. Reference Numerals in Drawings. 10 inlet basin 12 perforated basin cover 14 loop 16 filter basket 18 bridge 20 bridge ear 22 support bar 24 bar sleeve 26 cover support 28 bag assembly 30 separation

[0034] The letter L after a number refers to the left of the numbered item and R to the right.

[0035] The letter T after a number refers to the top of the numbered item and B to the bottom.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION FIGS. I-III

[0036] FIG. I best shows an exploded perspective of the invention in relation to its installed position in a typical rectangle inlet basin with a perforated cover. FIG. II shows the ridged support structure of the invention for a round inlet basin. FIG. III shows an exploded perspective view of the invention and installation arrangement in a round inlet basin beneath a perforated cover.

[0037] A bag assembly 28 comprises a filter basket 16 and two bar sleeves, 24L and 24R. The two bar sleeves enclose the two support bars 22L and 22R. The filter basket is made of a porous material with hydraulic openings smaller than the pollutants intended to be filtered from the storm water. The bag assembly is preferably made from a polypropylene geotextile fabric. However this filter may be made of many types of porous materials for example, cotton, burlap, or stainless, fiberglass, and aluminum mesh. The filter basket is connected to the support structure by means of sleeves.

[0038] The support structure comprises the support bars 22L and 22R and bridge 18. The bar sleeves, 24L and 24R, receive the support bars 22L and 22R. The bars stretch the sleeves across a portion of the inlet cover support 26. The bag assembly's remaining peripheral lip loops between the two support bars forming an overflow bypass. If no bypass is needed for a particular rectangular inlet basin, the remaining basin sides may also be equipped with support bars inserted into sleeves. When assembled together, the two bars rest on the cover ledges 26L and 26R and essentially in the corners of the basin. The support ledges are typically about two inches wide. In FIG. I, the support rods are fourteen gage galvanized sheet metal two inches wide and at least one inch shorter than the length of the ledge on which it rests. The rods rest flat on the cover ledges or supports underneath the perforated cover when the cover is in place. The length of the rods exceeds the distance between the opposite cover ledge supports 26T and 26B. In rectangular basins where there are support ledges on only two sides of the basin the bars lay at a 90 degree angle to the ledges on the two sides. Each bar extends onto each of the two ledges. Where the bars require extra strength to expand across the basin they are made of one inch galvanized angle iron. The angle iron is notched out back 4 cm. (1^(1/2)″) on each end in order to be able to rest flat on the two parallel ledges. The ends are then placed on the ledges and in a corner of the basin. The bridges 8L and 18R expand across the remaining sides of the basin. The bridges' composition is 18 gage 50-52 aluminum sheet metal. The bridge could comprise any suitable metal or fabric. For example a material the same as that which the filter basket is made of could be used. The bridge could also be attached directly to the basket. In our preferred embodiment, the bottom half of the bridge's length is notched out at each end back 4 cm. (1^(1/2)″) to form ears 20L and 20R. The bridge ears, 20L and 20R, rest on the top of the support bars in the basin's corners. The remaining lower portion of the bridge hangs between the two ridged support bars 22R an 22L and inside the filter basket 16.

[0039] In the round inlet basin design shown in FIG. II and FIG. III, the rods 22L and 22R form a single unit with the bridge 18. The bridge and support bars consist of one piece of 14 gage 50-52 aluminum sheet metal. This is essentially resistant to both wear and corrosion caused by its environment and storm water. The perimeter of the support structure is circular in formation and typically sized 5 cm. (2″) less in diameter than the inlet opening. The bars are disconnected at a separation 32. In FIG. III, the support bars are inserted into the bar sleeves 24R and 24L of the bag assembly 28. The sleeves slide around up next to the bridge cover 18 on each side. As best shown in FIG. I., the filter basket is looped between the two support bars under the bridge to form a bypass channel. The inside of the bridge, which extends into the center of the support structure, is bent downward covering the loop.

[0040] From the description above a number of advantages of my invention are apparent.

[0041] a) The parts are simple in design and inexpensive to fabricate.

[0042] b) The parts are simple in design and are easily sized to fit to the many varied sizes and types of inlet basins required.

[0043] c) In the design for rectangle basin inlets shown in FIG. I, the parts are not rigidly attached to each other and thus can move easily without serious damage if forced by a pivotal movement of the heavy perforated cover during service. The round filter shown in FIG. II and FIG. III can typically slide one inch under such conditions and thus avoid serious damage to the support structure.

[0044] d) In the design for rectangle basin inlets shown in FIG. I the support structure parts are not rigidly attached to each other and thus adaptable to most angle distortions found in rectangle inlet basins in the field.

[0045] e) There are no moving parts that can easily wear out, or otherwise malfunction.

[0046] f) The support structure consists of light sheet metal that can be easily hand cut to length at the point of installation when necessary.

[0047] g) The filter simply rests on the basin cover's ledge and there is no need to alter the basin to install the apparatus.

[0048] h) The thickness of the filter apparatus which rests on the ledge underneath the perforated cover will raise the level of the cover less than 5 mm. ({fraction (3/16)} inch) which will not be a hazard to traffic or street maintenance equipment.

[0049] i) The means of attaching the bag assembly to the support structure is sturdy yet allows the bag assembly to be easily replaced when necessary.

OPERATION OF MY INVENTION FIGS. II TO III

[0050] My invention removes and retains storm water pollutants within a storm water inlet basin 10. Storm water flows from the street through the perforated cover 12. Then it flows either across a support bar 22 inserted in its sleeve 24, or across a bridge 18. The storm water then flows into the filter basket 16. The baskets' filter material permits storm water to flow through the filter basket and into the basin chamber while retaining pollutants within the baskets' cavity. The filter's support structure comprises support bars and a bridge. The support bars rest below the perforated cover on the basin cover support ledge 26. The bars stretch the filter along the cover support or ledge. The enwrapped bars convey water from the adjacent opening rim of the inlet basin 10 into the interior of the filter basket 16. This enclosure also holds the bag assembly 28 in position within the inlet basin. The bars bear the weight of the filter while preventing the deformation of the bag assembly. In a rectangular inlet basin as shown in FIG. I., the support rods are longer than the basin opening directly below the cover ledge. The ends of the rods extend beyond the opposite two ledges of the basin angled at 90 degrees in relation to the bars. This extended length prevents the bars from slipping past the cover support and further down into the lower basin chamber. The bridge 18 covers the loop 14, between the support rods. The bridge conveys water from the adjacent inlet basin's periphery opening into inside the filter basket. In normal conditions, this prevents the storm water from prematurely dropping through an opening formed by the loop without passing through the filter basket. This loop droops lower than the sleeves to provide a bypass conveyance channel for excess high water to overflow directly into the basin's lower chamber. In the event of filter failure, or during high water flows, it is necessary for water to escape unhindered out a bypass channel. Otherwise the water would back up into the street or parking lot and cause a traffic hazard. The filter bypass channel is a space underneath the bridge cover, where excess water can overflow out over the loop, and down between the basket and the inlet basin walls. The filter basket and loop are formed so that the loop not only drops lower but also pulls away from the basin walls. Where this is not practical, a ridged structure can be placed between the filter basket and the adjacent wall to separate the basket from the wall allowing the water free passage. The bridge also serves a second function. It spreads the two support bars apart holding them at rest on the cover ledge. In the rectangle basin shown in FIG. I., the bridge ears 20L and 20R hang the bridge in place on the support bars and essentially in the corners of the basin.

[0051] The present invention is convenient to install. First remove the perforated cover 12 or grate. Install the rectangle design by inserting the two support bars 22L and 22R into the sleeves 24L and 24R of the bag assembly 28. Then lay each bar on the cover ledge 26 in the inlet basin 10. Where there are only two parallel cover ledges, instead of one continuous ledge, place the support bars perpendicular to the two ledges resting the ends of the bars on the ledges in the basin corners. Place the bridges on the two remaining sides of the catch basin. Lay the bridge ears 20R and 20L on top of the bars in the basin corners. Place the lower half of the bridge so that it hangs between the two bars and also inside the filter basket. Now replace the basin cover. Remove the invention in reverse order.

[0052] Installing the round design shown in FIG. II and FIG. III is also convenient. Lay the bridge with the interior edge bending downward inside of the filter basket. Insert a rod into one end of the bag. Slide the sleeve around and up against the side of the bridge. Next insert the remaining bar into the other end of the sleeve and move the sleeve around the circle to the other side of the bridge. Lay the assembled apparatus inside the rim on the perforated cover support. Now replace the basin cover 12. Remove it in reverse order.

[0053] Servicing the filters is convenient. They can be either vacuumed or pulled out by hand and emptied.

SUMMARY RAMIFICATION AND SCOPE OF MY INVENTION

[0054] Accordingly the reader will see that this invention can be used to remove pollutants from storm water within an inlet basin before the water is released down stream from the basin. One can also see that it is economical to manufacture, install and service. Furthermore my invention for an inlet basin has the additional advantages and objects:

[0055] a) To provide a filter that easily installs and removes, by hand without tools;

[0056] b) To provide a filter with a support structure that moves easily within the cover support ledges so it can give room for the typically heavy inlet cover to pivot on one end during removal and replacement without serious damage;

[0057] c) To provide a filter, that is not a ridged frame, and so it can easily lay into the occasional inlet that is out of square;

[0058] d) To provide a filter that has a support structure which is entirely inside the catch basin and raises the permeable cover less than {fraction (3/16)} inch and thus does not interfere with the normal traffic flow of street vehicles or street maintenance equipment;

[0059] e) To provide a filter that can easily be cut with simple hand tools and fitted at the installation site when necessary;

[0060] f) To provide a filter that is entirely below the permeable cover and thus essentially impervious to vandalism;

[0061] g) To provide a filter that requires no need for attachments to the permeable cover which would make the heavy covers' removal and handling more difficult;

[0062] h) To provide a filter that permits many types of filter materials to be easily interchanged for various degrees of filtration;

[0063] i) To provide a filter that can position a chemical absorbent medium inside of a curb inlet for the removal of such pollutants as hydrocarbons;

[0064] j) To provide a filter that can serve as either a permanent or short term Storm Water Prevention Plan (SWPP) measure;

[0065] k) To provide a filter, that has a bypass enabling storm water to flow downstream in the event of a filter failure, or to accommodate excessive storm water flows.

[0066] Although the description above contains many specifications, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the presently preferred embodiments of this invention. Thus the scope of the invention should be determined by the appended claims and their legal equivalents, rather than by the examples given. 

1. I claim: a) In a storm water inlet basin comprising b) a perforated cover that rests on c) a cover support within a top opening of the basin d) in a filter located within the basin a) essentially below the inlet basin's cover b) a filter comprising a support structure and a filter bag assembly suspended thereon wherein said support structure comprises an elongated ridged material inserted into a sleeve formed on a periphery portion of the bag assembly where the ridged material stretches said sleeve across a portion of said cover support holding the bag assembly in place within the inlet basin and conveys water from the inlet opening rim into the interior of a filter basket of the bag assembly.
 2. The filter of claim 1 further includes a filter bypass means comprising a loop formed in an upper periphery of said filter basket where the basket hangs lower than the remaining lip of the filter basket and between two ridged supports and where said loop forms a channel for excess water to escape over the edge of the loop out of the basket cavity and into the basin's lower chamber and said filter bypass means further comprises a bridge which conveys unfiltered storm water from the adjacent basin's opening, above and over said loop, and into the inside of the filter basket.
 4. The filter basket of claim 1 wherein the basket comprises permeable geotextile fabric, whereby a material with recognized standard specifications may be used with predictable filtration results.
 5. The support structure of claim 1 wherein the ridged supports are metal rods whereby the strongest materials may be used within the smallest space thereby keeping the perforated cover safe for traffic and maintenance equipment when the invention is installed.
 6. I claim a) in a storm water inlet basin comprising b) a perforated cover that rests on c) a support within a top opening of d) an inlet basin with e) a perforated cover f) a filter located essentially beneath said inlet basin's perforated cover g) within the basin cavity comprising h) a support structure and i) a filter basket suspended thereon and thereby held in place within the inlet basin an attachment means for joining the filter basket to said support structure wherein said filter basket is joined to the support structure by a sleeve enclosure around a ridged elongated portion of the support structure.
 7. The support structure of claim 6 wherein the ridged supports are metal rods which give the strongest support within the smallest amount of space and thereby takes up the smallest amount of space between the cover support and cover when installed.
 8. I claim in a filter a) located within a storm water inlet basin b) with a perforated cover c) that rests on a support within the top opening of said inlet basin d) with a filter bag assembly located beneath the cover comprising e) a support means to hold the assembly in position within the inlet basin, a filter bypass means comprising a loop formed in a peripheral portion of said filter bag assembly where the bag assembly comprises a filter basket that hangs between two ridged supports and hangs lower than the bag assemblies remaining periphery whereby said loop provides a channel for excess water to escape out of the basket cavity over the edge of the loop and fall into the basin's lower chamber and said filter bypass means further comprises a bridge which, during normal conditions and functions conveys unfiltered storm water from the inlet's peripheral opening, above and over the loop and into the inside of said filter basket.
 9. The bridge in claim 8 wherein the bridges' composition is of aluminum sheet metal that is essentially resistant to corrosion caused by its environment and storm water.
 10. The ridged supports of claim 8 further includes a support structure comprising elongated ridged material inserted into sleeves formed on the periphery of a filter bag assembly and stretches the sleeves across a portion of the basins' perforated cover support holding the filter bag assembly in position within the basin and also conveying storm water into the inside of the filter basket. 